The present invention relates to an apparatus for discriminating printed matter such as bank notes or the like, and more particularly to an apparatus for distinguishing the genuineness from the spuriousness of printed matter or for discriminating the kind or sort of printed matter, for example, the denominations of bank notes.
The Japanese Patent publication TOKKAI No. 177592/86 discloses a method for discriminating printed matter, in which the analog output of a magnetic sensor and reference data are compared with each other while being relatively shifted in their addresses, to thereby discriminate printed matter. However, this method identifies the coincidence or noncoincidence of a series of sampled data with the reference data, which sampled data is formed by standardizing the analog output of the magnetic sensor with a fixed level of threshold. This is nothing but the comparison of the pulse width between the sampled data and the reference data, and makes no effective use of individual or minute pulse amplitude data. Therefore, such a disadvantage of the prior art cited in the foregoing occasionally hinders a higher improvement in the discriminating accuracy.
It is therefore, an object of the present invention to provide an apparatus for discriminating printed matter which is capable of achieving a much higher improvement in the discriminating accuracy by using the basic operation thereof in which the analog signal from the magnetic sensor is converted into digital data each informing the amplitude thereof, with an A-D converter means, and the digital data are compared with the reference data to check if the amplitude of the analog signal is within the allowable limit while being shifted in their addresses.